def change
  <%=
  case database_adapter_name
  when /mysql/i
    'add_column :users, :display_name, :string, limit: 191'
  when /sqlite/i
    <<~'RUBY'
      add_column :users, :display_name, :string
      change_column_null :users, :display_name, false
    RUBY
  else
    'add_column :users, :display_name, :string, null: false'
  end
  %>
  DbTextSearch::CaseInsensitive.add_index connection, :users, :display_name,
                                          unique: true
end
